Wheat

WheatAn annual plant of Gramineae or Poaceae family

Genus Triticum

Species: Triticum aestivum L.

Triticum aestivum or common wheat or Bread wheat

Types: many kinds of wheat in the world today.

The two most common are common wheat, Triticum aestivum, also known as bread wheat account for some 95% of all the consumed wheat in the world today; and durum wheat T. turgidum ssp. durum, which is used in pasta production.

T. turgidum & T. durum (durum wheat)

Dru na gu Dzongkha Bumthapkha Sharchopkha Lhotshamkha

Rice Bja/ray Thrung Bara Dhan

Maize Gheyza Ashom Aashum Maakai

Wheat Ka Ka Bong Gaow

Barley Naa/Nay nak Phemong Zaoun

Sweet Buckwheat Jarey Cha-rey Khala Methey Fapar

Bitter Buckwheat Bjo Brathma Gungtshung/ Braima

Tithey Fapar

Finger millet Memja Kongpo Kongpo Kodo

Foxtail millet Yangra Ran Yangra Kaguni

Common millet Chham Cheyra Kodo

Amaranth Aaiam/Zim tse maap

Moo/Lasom Lathey

Mustard Paeka Yungkar Mema Tori

Pulses Sem sem Sem chung rik Dal

Importance of wheat in the world• wheat, rice and corn account for 75% of the world’s grain

production and 56% of the world’s food energy.• wheat is the second most-produced food among the cereal

crops• Wheat grain is a staple food used to make flour for breads;

cookies, cakes, breakfast cereal, pasta, juice, noodles; and for fermentation to make beer, alcohol, vodka or biofuel.

• Although wheat supplies much of the world's dietary protein and food supply it contains a protein called gluten – coaliac diseases –wheat allergy (sensitive)

In Bhutan• source of income, (3rd most important food crops

grown in Bhutan after rice and maize).• uses same as mentioned above

Top Ten Wheat Producers — 2005(million metric ton)

 China 96

 India 72

 United States 57

 Russia 46

 France 37

 Canada 26

 Australia 24

 Germany 24

 Pakistan 22

 Turkey 21

World Total 626

Source:UN Food & Agriculture Organisation (FAO)

Important growing countries

Source: MoA, 2006: Agriculture Statistics.

In Bhutan

• Cropping system: • generally grown in dry land (53.9%) as main crop

from 300m to 3000masl.

• Also grown in wet land as secondary crop after rice (rice-wheat system, consists of 80%), maize, potato & in rotation with Buckwheat at higher altitude.

• significant part of the wheat crop is generally cut as green fodder for cattle, the remaining is harvested to supplement food consumption.

• For eg. Winter fodder up to 2500 masl & for haymaking at elevations of 3500-4000 masl.

Origin:

11000BC in middle east; 4000 BC in asia, europe and NAmeriaca..earliest grown crop.

• In Bhutan: believed to have been introduced from Tibet.

History: wild ancestor is Triticum boeticum, fertilized with wild grass called aegilop speltoids to give the modern wheat.

Species & Varieties• 18 species recognized• Most important to agriculture are:• T. aestivum (common wheat); T.monococcum (Einkorn or

Europena wheat), T. turgidum & T. durum (durum wheat), T. compactum (club wheat); T. dicoccum (emmer wheat - wild sp. Wheat & closely related to durum wheat).

Genetics: Some wheat species are diploid, with two sets of chromosomes, but many

are stable polyploids, with four sets of chromosomes (tetraploid) or six (hexaploid).

• T. aestivum: A hexaploid species that is the most widely cultivated in the world.

• T. durum: The only tetraploid form of wheat widely used today, and the second most widely cultivated wheat.

• T. monococcum (Einkorn): A diploid species with wild and cultivated variants. Domesticated at the same time as emmer wheat, but never reached the same importance.

• T. dicoccon(Emmer): A tetraploid species, cultivated in ancient times but no longer in widespread use.

In India

• T.aestivum or vulgare (common bread or bread wheat) – chapati & bakery products – grown all over India

• T.durum (durum wheat) – suji, sphagetti & macaroni – grown in Central & South

• T.dicoccum – (emmer wheat) grown in South India.

In Bhutan• Many landraces or indigenous wheat varieties

replaced by Jaga ka• All wheat varieties grown in the rice-wheat system

are Introduced spring wheat grown during winter

1. Sonalika: – early maturing variety – susceptible to yellow (stripe) or brown (leaf) rust.

2. Bajoka -1 & 2.

2a. Bajoka-1: recommended for medium & low alt.

– matures 155-160 days

– Grows to a height of 80-85cm tall- Yields 2.5 – 3.0 tons per hactare

- moderately resistant to yellow and brown rusts.

Bajoka-2:

• - recommended for low altitudes

• - matures 150-160 days

• - Grows to a height of 100cm tall

• - Yields 2.5 – 3.0 tons per hac

• - highly resistant to yellow and brown rusts

Dist. Features:

Sonalika and Bajoka variety

Sonalika:

Height taller than Bajoka 1&2,

Spike turns yellow, leaf blade bit bigger. In

Bajoka

Bajoka I spike remains white & straight until maturity while spike bends at maturity for Bajoka 2 but colour remains unchanged.

Morphology

• Two distinct parts: Root and Shoot system• Root System: Pry or temporary root system

Secondary root system/permanent root system

- Starts with the formation of a radicle (embryonic root) at the time of seed germination –

- Arises at the depth where the seed is planted- absorbs nutrients for young seedling- Growth progresses, the pry root system dies and

is replaced by more permanent Secondary Root System (PRS)

Secondary Root System

- Arises at the point above the PRS as the main organ of absorption of nutrients for matured seedling/plant

- Arises near the soil surface at about 21-25 days after seed sowing (i.e. at the time of crown root initiation stage)

-

• Shoot System –all parts above the ground• - Stems, leaves and inflorescence

(flowering & fruiting)• Stem & inflorescence = culm1. Stem: round & cylindrical, hollow except

at the node (solid)2. Leaves: 4 parts – Leaf sheath, leaf blade,

ligule, auricleLeaf sheath: basal part of the leaf –

surrounds the culm (stem) & protects the growing point and auxillary buds from weather – also provide support to culm (stem).

http://www.missouriplants.com/Grasses/Triticum_aestivum_page.html

• Leaf blade – flattened, parallel venation – function?

• Ligule – soft membranous part at the junction of the sheath and the blade

• Auricle – claw-like appendages projecting from the collar of the leaf.

3. Inflorescence – flowering portion – ear or head or spike – consist of spikelet, florets, kernel

- spikelets are systematically arranged in a zigzag manner along a common axis (rachis)

- Wheat is a monoecious plant with perfect flowers. It reproduces sexually as a self-pollinated crop.

• Spikelet: composed of flowers called florets

• No. of florets in a spikelet vary from 1-5

• Florets in each spikelets are enclosed by two glumes

• Florets: outer covering – lemma & palea• These are hardened, modified stems that protect the floral

organs. • The lemma is relatively larger than the palea. • When the spikelet is closed, the lemma partly encloses the

palea. • The pointed end on top of the lemma is called an awn.

Grain or Kernel or caryopsis - fruit formed from a single carpel

- The caryopsis is popularly called a grain and is the fruit typical of the family Poaceae (or Gramineae), such as wheat, rice, and corn.

- 3-10 mm in length, 3-5 mm in diameter

- Embryo – rich in protein called gluten- coaliac

diseases –wheat allergy (sensitive) & fats

- Bran – testa or pericarp – by-product of milling & used as feeds.

Carbohydrates     51.8 g

- Dietary fiber  13.2 g  

Fat 9.72 g

Protein 23.15 g

Thiamine (Vit. B1)  1.882 mg   145%

Riboflavin (Vit. B2)  0.499 mg   33%

Niacin (Vit. B3)  6.813 mg   45%

Pantothenic acid (B5)  0.05 mg  1%

Vitamin B6  1.3 mg 100%

Folate (Vit. B9)  281 μg  70%

Calcium  39 mg 4%

Iron  6.26 mg 50%

Magnesium  239 mg 65% 

Phosphorus  842 mg 120%

Potassium  892 mg   19%

Zinc  12.29 mg 123%

Manganese 13.301 mg

Wheat germ, crudeNutritional value per 100 g

Energy 360 kcal   1510 kJ

Percentages are relative to USrecommendations for adults.

Source: USDA Nutrient database

Carbohydrates     79 g

- Sugars  0.12 g

- Dietary fiber  1.3 g  

Fat 0.66 g

Protein 7.13 g

Water 11.62 g

Thiamine (Vit. B1)  0.070 mg   5%

Riboflavin (Vit. B2)  0.049 mg   3%

Niacin (Vit. B3)  1.6 mg   11%

Pantothenic acid (B5)  1.014 mg  20%

Vitamin B6  0.164 mg 13%

Folate (Vit. B9)  8 μg  2%

Calcium  28 mg 3%

Iron  0.80 mg 6%

Magnesium  25 mg 7% 

Manganese  1.088 mg 54% 

Phosphorus  115 mg 16%

Potassium  115 mg   2%

Zinc  1.09 mg 11%

Rice, white, long-grain, regular, & raw

Nutritional value per 100 g

Energy 370 kcal   1530 kJ

Percentages are relative to USrecommendations for adults.

Source: USDA Nutrient database

http://weedsoft.unl.edu/documents/GrowthStagesModule/wheat/wheat.htm#

http://sanangelo.tamu.edu/agronomy/wheat/whtmang.htm (Refer)

Growth Stages

Jointing Stage- Is a part of the veg. stage, characterized by:- Stem elongation- Most tillers have formed by this stage and the secondary

root system is developing- Plants begin to grow erect from its previous prostate growth- the number of spikelets per spike (head size) is determined. - The first node just above the soil surface is visible on the

main stem followed by second node as well as nodes on tillers

- rapid spike expansion take place. - Flag leaf becomes visible just after the second node on

main stem

At the boot stage, the head is developed and can be seen in the swollen section of the sheath of the flag leaf.

Heading and Flowering

Heading

- At this stage awns are visible and heads are emerging through the slit of the flag leaf sheath, with approximately 50% of heads emerged from the flag leaf in a given area.

Flowering

- At this stage heading is complete.

- Flowering begins about 3 to 5 days after heading, first on the main stem followed by on the tillers.

Ripening

- This stage denotes physiological maturity. This is followed by kernel ripening and grain drying.

Climatic requirement – Wide adaptability- Prefer areas with cool, moist weather during

growing period followed by dry, warm weather.

- Optimum temperature range for ideal germination of seed is 20 – 25 degree Celsius

- Can germinate in the temp range of 3.5 – 35 deg.C

- Areas with warm and damp climate are not suited for wheat growing.

• Cloudy weather, with high humidity and low temp. is conducive for rust attack.

• Requires about 14 -15 deg. C at the time of grain filling & is crucial for yield

• Temp above 25 deg C tend to affect yield

Soils: SOIL- Soil type is the most important local physical

feature affecting cropping potential and management practices.

- Wheat grown in variety of soils- Preferred soil types are clay loam & heavy soils

with good drainage.

- Eg. Gangetic alluvium of UP and Bihar, Indus alluvium of Punjab and Haryana etc.

Field Preparation

- Requires a well pulverized soils for good germination

- Field after the harvest of previous crop should be properly ploughed and harrowed 2-3 times followed by planking

- Pre-sowing irrigation (wetland) 7-10 days before sowing seed is needed for proper germination.

• Light leveling is required before sowing seed.

• In rain-fed areas (dry land) – FP should be done with care as conservation of moisture is dependent on it.

• Fields are deep ploughed and done planking

• Usu. done in evening times and furrow should be kept opened whole night to absorb moisture from dew.

• Planking should be done in the morning

Seed and sowing

- Certified seed of right variety suitable for a particular locality should be selected

- Seeds should be treated with Vitavax @ 2.5g/kg seed to control loose smut.

Time of Sowing

- One of the important aspects in obtaining good yields of wheat

- Varies widely over the wheat growing areas

- Depends on soil temperature, irrigation facilities and duration of wheat varieties

- Rainfed wheat is sown in 2nd week of Oct – beginning of November.

• Irrigated varieties sown in the beginning of November

• Sonalika (short duration variety) is sown sometimes in the month of Dec.

• However, when wheat is sown in the month of Dec., there is a drastic reduction in yield.

Method of sowing: Four methods1. Broadcasting – uniformly broadcast and

then covered by harrowing (commonly practiced in Bhutan)

2. Behind local plough – commonly practiced in India – seeds are dropped by hand into furrows that have been opened with last plough

3. Drilling – sown by seed drill by dropping seeds at uniform depth - Results in uniform germination

- Seed drill may be bullock or tractor driven

4. Dibbling: – used in case supply of seeds is limited – done with the help of a small implement called “Dibbler”

- Not commonly used – time consuming

Management practices

Manures and Fertilizers:

- MF both play an impt roles in crop prodn – impt in wheat cultivation

- About 5 t/ha of well decayed FYM at final

- land preparation and is mixed well- for better yield supplement with inorganic

fertilizers @ 50:30:20 NPK kg/ha- half of N and all of P & K should be applied

basally while the rest of the N should be top-dressed at first irrigation

Seed rate: 100-130 kg/haSpacing: 20 - 22.5 cm between rows is

recommended & when sowing is delayed a closer spacing of 15-18cm adopted.

Irrigation- Adequate soil moisture is required for normal dev. of

wheat plant at all stages of growth.

- A total 5 irrigation – crown root initiation (CRI) (20-25); tillering stage (40-45); jointing (booting) stage (70-75); flowering (90-95); dough stage (110-115).

- vary depending on soil type, winter rainfall, amount of water applied per irrigation; 3 sufficient.

• The crown root initiation (CRI) stage and heading stage are the critical stages when plant suffers most due to moisture stress.

• 1st Irrigation: 20-25 or 25-30 days (hilly areas like Bhutan) after sowing i.e. at the CRI stage.

• Delay avoided – upset root growth, tillering, heading and yield.

• 2nd Irrigation: at booting or jointing stage (70-75 days after sowing)

• 3rd Irrigation: At milk stage (90-100 days)

Harvesting

- when leaves and stems turn yellow and become fairly dry – before it is dead ripe.

- Done manually using serrated sickle - In villages using 2 short sticks called “Khrip or

Kreow”

Harvesting

- Usually done by cutting the head with sickle or cutting the entire stem

- The cut stem with ears are bundled up and hanged to dry

- When dry, ears are cut from the peduncle and beaten with stick or crushed with feet.

Threshing: after harvest dry the crop for 3-4 day, then stack and thresh.

- Manually using a flail (Kubji or yarjung) or power thresher.

- made of two sticks joined by a knob, one for a handle and the other which swirls in a clockwise direction, threshing the crops

Storage:- Moisture content for

safe storage is 10-12 %

Weeds – both dicot and monocot

- Major dicot weeds are: Chenopodium album, Fumaria parviflora, Cirsium arvense, Anagallis arvensis etc

- Monocot weeds include: Phalaris minor, Avena fatua (wild oat), Cyperus rotundus, Cynodon dactylon

Phalaris minor (Dwarf Canary Grass)

Cyperus rotundus or Nutgrass

Weed control

– eradicated with the help of hoe and uprooting by hands

- Chemical weedicides are used - Common & effective herbicide (liquid & solid)

used to kill broad-leaved weeds is 2,4 D (2,4-dichlorophenoxy acetic acid).

- 700 ml/625gm is mixed with 400-600 lts of water for spraying in an area of one hectare.

- Sprayed 32-35 days after sowing

- Spraying after 40 days not effective or not beneficial.

• Avoid drift of spray in the adjoining crop fields, a slight drift may spoil pulse crop (pea, lentil, mustard)

• Monocot weeds like Phalaris minor can be controlled by spraying Tribunil/Dosanex/

Isoproturon @ 2kg per ha in 400-600 lts of water at 32-35 days.

Wheat Diseases

- Major diseases of wheat are rusts, loose smut, alternaria leaf blight & powdery mildew.

- Rusts (brown & yellow) – caused by fungus sp. Puccinia. Black rust also appears in fields that are sown late.

Brown rust

– Puccinia recondita tritici

• Generally develop on leaves but in severe attacks - on sheath and stem (scattered)

• uredial pustules are bright orange in color, which are in small clusters or irregularly scattered.

• Spreads during warm and humid conditions

• In severe attacks, plant mature early, produce light and shrivelled grains & poor dev. of roots.

• Most widespread in India

Yellow rust• Fungus Puccinia straciformis • Generally develop on leaves but in

severe attacks - on sheath, stem and glumes

• uredial pustules are lemon-yellow in color, which are in rows

• Appearance of lemon-yellow pustules in rows is characteristic feature

• In severe attacks, these pustules become large patches & plant gets completely covered

• Common in areas where temp gets considerably low during the wheat growing season

• Problem of the hills, foot-hills.

Black rust:

Puccinia graminis tritici

- Uredial pustules occur on stem, sheath, leaves and earheads

- stem severely affected.

- Formation of dark, black, elongated telial pustules

- Spreads during warm and humid conditions

Rust control measures- Avoid growing single variety in entire field – adopt

2-3 varieties- Avoid late sowing as late sown crop is susceptible- Avoid excess use of nitrogenous fertilizers as high

dose of nitrogen favours rust formation- Spraying Zineb or Dithane M-45 with Sandovit- Spraying is recommended if good crop is

threatened- 1st spray when pustules are seen @ 375 lts solution

per ha- 2nd spray after 10 days @ 750 lts solution per ha- 3rd & 4th spray at the interval of 14 days @ 1000 and

1250 lts soln per ha, respectively

Other diseases:• Loose smut – smut fungus,

Ustilago nuda tritici• Distinguishable after heading from

healthy plants• Production of black powder in

place of grains in the ears -every ear is converted into black powder

• Is a mass of olive-green microscopic spores – blown, germinate on the female organ, stigma leading to infection of developing seed.

Control: - resistant variety, Vitavax- uproot the infected plant (cover the black spores) and burn it.

Alternaria leaf blight - Fungus, Alternaria triticina- Lowermost leaves show

the sign of infection first and spread to upper leaves

- Small, oval, discoloured lesions, irregularly scattered spots on leaves

– become dark brown and irregular - Death of entire leaf

Control – Vitavax and spraying Zineb

or Dithane M-45

Powdery Mildew: - Fungus, Erysiphe graminis

tritici- Characterized by formation

of white, powdery growth of the fungus (spores) on the upper surfaces of leaves

- Leaf sheaths, stems and earheads may also be affected when severe

Control – resistant variety – burn crop residues after

harvest